The global data traffics increase explosively, and newly-emerging services represented by video and streaming media services develop rapidly, such that data services with dynamic, high-bandwidth and high-quality requirement become the main body of network traffics, and drive the network to evolve towards the packetization. On an aspect of a transport network, it can be seen that the development is from a traditional Synchronous Digital Hierarchy (SDH) circuit switching network to a Multi-Service Transfer Platform (MSTP, which is based on the SDH) with multi-service access functions, and then is gradually evolved to a Packet Transport Network (PTN) nowadays, which is exactly the result of the development of network traffic datamation. Fundamentally, the circuit switching network can only provide the rigid pipeline and coarse granularity switching, and cannot effectively meet the requirements of dynamism and burst of the data services, but the flexible pipeline and statistical multiplexing feature of the packet switching network are naturally suitable for the data services. However, the current packet switching is basically processed based on the electronic layer, and the cost and energy consumption are high, and with the rapid growth of the traffics, the processing bottleneck of the current packet switching is increasingly prominent, which is difficult to adapt to the high-speed, flexible, low-cost and low-energy requirements of the future networks. The optical network has an advantage of low cost, low energy consumption and high speed and large capacity, but the traditional optical circuit switching networks (such as Wavelength Division Multiplexing (WDM) and an Optical Transport Network (OTN)) can only provide the large granularity grid pipeline, which is short of the flexibility of the circuit packet switching and cannot effectively bear the data services.
In the access network, the Gigabit-Capable Passive Optical Network (GPON) technology combines the advantages of the optical layer and the electronic layer to a certain extent. In a downstream direction, the GPON technology, by means of optical layer broadcast, distributes a downstream signal transmitted by an Optical Line Terminal (OLT) to multiple Optical Network Units (ONUs) via an optical splitter, and meanwhile, a bandwidth map of an upstream frame is carried in a downstream frame header, to indicate the transmitting time and length of the upstream data of ONU. In an upstream direction, each ONU transmits the data according to an indication of the bandwidth map, and multiplexes the data to one wavelength path via an optical coupler and uploads the data to the OLT. Therefore, the GPON possesses the characteristics of high speed and large capacity and low cost of the optical layer on one hand, and implements the optical-layer statistic multiplexing of the multi-channel data in the upstream direction on the other hand, which improves the flexibility and the bandwidth utilization. The GPON normally uses the star/tree networking topology, and a working principle thereof is suitable for bearing the multipoint-to-single-point converged traffics (the north-south oriented traffics predominate), thus the successful application and large-scale deployment are achieved in the access network.
However, with respect to a non-converged application scenario, such as a metropolitan area core network and a data center internal switching network, the east-west oriented traffics account for a large proportion and even occupy a leading position, thus the GPON technology is apparently unsuitable (the east-west oriented traffics need to be forwarded by the electronic layer of the OLT, but the capacity of the GPON is limited). The Optical Burst Transport Network (OBTN) adopts all-optical switching technology based on the Optical Burst (OB), and possesses the capabilities of optical layer bandwidth on demand and fast scheduling between arbitrary network node pairs, which can realize the dynamic adaptation and good support to multiple traffic (such as north-south oriented burst traffics and east-west oriented burst traffics, etc.) scenarios, and can enhance the resource utilization efficiency and network flexibility, and maintain the advantages of high speed and large capacity and low cost of the optical layer in the meantime, and be suitable for multiple star/tree/ring network topologies.
Optical Burst Transport Network (OBTN) is an optical transmission technology of wavelength division multiplexing of which the granularity is between Optical Circuit Switching (OCS) and Optical Packet Switching (OPS). The key idea of the OBTN is to take full advantage of the huge bandwidth of optical fiber and the flexibility of electronic control, and separate the control channel and data channel. The data channel performs the all-optical switching technology by using the data frame based on the Optical Burst (OB) as the switching unit, while one control frame in the control channel corresponds to one data frame, which is also transmitted in the optical domain, but at the node, it is converted to the electric domain for processing to receive and update the corresponding control information, and is in the continuous transceiver mode. It can be understandable that, there may be more than one data channels, or there may be more than one control channels.
A device of the optical burst transport network needs a control channel to transmit the control information. Each device controls the burst reception and burst transmitting of the optical signal of the data channel at each node device according to the received control information, and the OBTN network needs that one control frame corresponds one data frame to transmit. In the complex mesh OBTN optical burst transport network, on the one hand, there are multiple transmission paths from node to node, and on the other hand, the transmission of the data channel optical signal on any fiber at any node in the entire network needs the control frame with no collision to control. Currently, for the complex OBTN network, there is no mature implementation scheme.